derby



(No Model.)

G. MGC. DERBY.

ROCK DRILLING APPARATUS..

PNG. 278,517.

, Patented May 29,1883.

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UNITED STATESA PATENT Quince-,

GEORGE Meo. DERBY, oF NEW Yonk, N. Y.

'hoCK-DRILLING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 278,517, dated May 29,18183.

l 4 Application tiled November 14, 1882. (No model.)

To all whom fit may concern:

Be it known that I,GEORGE MoU. DERBY, a citizen of the United States,and residing in' the city, county, and State of New York, have inventedcertain new anduset'ul Improvements in Rock-Drilling Apparatus, ot'which the fol-V lowingis a specification.

y My invention belongs to that class ot' drills denominated tubular,inwhich the bit or cutting-edge of the drillis formed upon or attached tothe end of a tubular steel,and by the action of which an annular sectionof the rock operated upon is cut away. The advantage of this class isthat the labor that would be` expended in pnlverizing the interior issaved. It belongs also to the class` known as reciprocating, which areoperated upon the principle of the steam-hammers; These havetheir shankconnected to a piston working in a cylinder. Steam or compressed air,being admitted alternately before and behind the piston,forces itrapidly to and fro, causing the drill to strike the rock with greatrapidity and force.` The advantage of the reciprocating drill, besidesthe rapidity of itsoperation, is that it can be used to drill a hole atanyangleto the vertical.

Heretofore, so far as myknowledge extends, i it has notbeen foundpracticable to operatea tubular drill withthis class of machine, butonly drills hav-ing a solid steel` and bit have y been so worked. Thediamond `drill is tubular, butis worked onlyby a constant revolutionabout the axis of the tubo and scratches away the rock without striking.

' The practical difticulties to be' overcome in using a tubular bit onthe class of machinedrills above described are, first, to dispose of.the core formed; and, second,to prevent the steels, thus uniting the.classes. f

`My invention consists in pitching up the end or bit of the drill andshapingthe cuttingedges in such` a manner as to rapidly break the rock,and to prevent clogging either on'the outside or inside of theV tubularshank-steel.

advantages of both `It consists, also, in applying a streamof water,air,` or steam to remove the broken material'from the bit, soften therock,and preserve the temper of the drill. y

In the accompanying drawings, Figure l is a vertical section of atubular drill embodying my in vention, together with `a device forcommnnicating reciprocating motion thereto and supplying water or otherfluid to the bit of the Yceiving the extremity ot' the drill-shank D,

and to theother extremity of the shank D is secured, in any suitablemanner, the tubular drill E, hereinafter described. Theshank D is alsotubular, its perforation communicating at one extremity directly withthat ofthe rod 0,1and at the other extremity with the interior ofthetubular drill E.

Surrounding the rod G at its upper extremity is a cylindrical air orHuid chamber, F, with which communicates an inlet-tube, G, for supplyingair, steam, or water from any suitable reservoir and under any desiredamount ot' pressure. t t

VSuitablepacking-boxes, a andf, surround the piston-rod C at the pointswhere it passes through the heads of the cylinders A and F. Suitablepacking' is provided, andV the two cylinders are tirmlyunited by meansof suitable pressure-screws, a andf. ,A transverse aperture, c', leadsfrom the exterior ot' the piston-rod C, at a point within the air Vorfluid chamber F, into the center of the same, and

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communicates with the longitudinal perforation c2. The aperture c is atall times Within the cylinder F, and through it the Huid is vforcedcontinuously into the interior of the rock away from the bit of thedrill, and thus from the hole, as it is being formed, thereby obviatingthe difficulties arising from the clogging of the drill, and to preventthe drill from becoming overheated and its temper thereby destroyed.

To provide clearance and keep the drill from lbeing clogged bytheaccumulation ot' debris about its extremity near the bit, either uponthe inside or outside, it becomes necessary that the cutting-edge ofthedrill should be wider than the steel immediately above it, and Itherefore construct the same in substantially the manner shown in Figs.2, 3, and 4. This construction consists in forming the face of the bittransversely serra-te, as shown lin Fig. 2, and at the same timeswelling or expanding it upon its inner and outer edges. By renderingthe cutting-edge serrate it will rapidly pulverize the rock againstwhich it is driven, and by constructing the cutting-edges Wider than thesteel ot' the drill the dimensions of the-hole formed will besut'ticient to permit the drill to be reeiprocated without unduefriction, and. the size ofthe core of rock cut by the inner edge ot' thedrill will be such as to extend within the same without in anymannerintertering with the motion ofthe drill.

For the purpose of conveniently obtaining the required expansion oftheface ofthe drill, I prefer to form anyy convenient number ot'rtransverse wedge-shaped, teeth, e, around the extremity ot' the drill.The inner edges ofthe adjacent teeth meet eachother at their respectivebases, as shown at e', and the surplus metal, obtained by forming `thetriangular openings between the same, is thrownout uponeach lateralVsurface ot' the teeth, thus causing the face e2 ot' each tooth to be ofgreater width than its base. The result of this method of forming thecutting-edge or bit is that it presents to the rock a polygonal `figure,as seen iu Fig. 3, the lines joining the outer ends of the cutting-edgesot' the teeth forming a regular iigure,`the number ot' sides dependingupon the number of, teeth. v

The form given tothe face ol' the drill in carrying out my inventionwill depend both upon the size ot' the hole to be made and the materialto be operated upon. If a large hole is tobe made,'it is important tohave the core remain unbroken, so that it can be removed in as largepieces or 'sections as possible, thereby saving the power that wouldbenecessary to pulverize it; or it' the rock operated upon is very hard,then it again becomes important to leave the core unbroken. To dothisit'is necessary that the teeth of the drill vbe pitched up both onthe inside and outside, as represented in Fig. S-that is, the face ofthe teeth should extend beyond the surface of the tubular steel both onthe inside and ou the outside. In such cases the tubular steel must benearly as long as the distance the machine feeds. On the other hand, it'the hole to be drilled is small, or it' the rock is soft and easilypulverized, it is not always necessary to pitch up the inside of theteeth in this manner, the pitching up of the outside being sufficient.The drill, then, by its action breaks oft' the core in small sectionsand soon pulverizesit, the dbris of which is carried away with the rest.

It will be apparent from an inspection of the drawings that thetriangular spaces formed between the teeth and extending above theirbasis provide abundant clearance for the escape ofthe debris. Theexpansion of the steel commences as near the base ofthe teeth as isexpedient for combining the requisiteenlargement and strength.

1 do not herein broadly claim a tubular rock-drill attached to atubularshank, in com-v bination with mechanism for communicating a positiveto-'and-fro motion thereto, and for forcing a stream ot' air or watertherethrough, as I contemplate embodying the same in an application tobe hereafter tiled by me.

I claim as my invention- 1. A tubular rock-.drill having its bitorcutting-ed ge composed ot' wed ge-shaped teeth the cutting-edges ot'which are Wider than their bases, so arranged that lines joining theirouter edges shall form a polygon, and having triangular recesses betweensaid teeth and extending above their bases for the escape of dbris.

2. The combination,substantially as hereinbefore set forth, of a tubularrock-drill, a

Vtubular shank rigidly secured to said drill,

mechanism for giving a positive to-and-fro motion to said drill, means,substantially such as described, for supplying air, steam, or waterthrough the interior of said shank and drill to the bit of the drill,and a bit or cuttingedge to said drill, composed of Wedge-shaped teeththe cutting-edges of whichl are wider than their bases, so arranged thatlines joining their outer edges shall form a polygon, and havingtriangular recesses between said teeth and extending above their basesfor the escape of dbris.

In testimony whereof I have hereunto subscribed my name this 11th day ofNovember, A. D. 1882. v GEO. MCO. DERBY. Witnesses:

DANIEL W. EDGEooMB,

CHARLES A. TERRY.

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